Appendix E ------ Eradication and Control Attempts
Many different strategies to combat CWD have been employed around the country with
varying levels of success. For disease eradication, early detection of CWD infected animals
is paramount. The time between introduction and detection of the disease is the most critical
factor impacting an agency’s ability to control and possibly eradicate the disease before it can
become established. Once the environment becomes a reservoir for CWD prions, mitigating
the spread of the disease may be the only reasonable course of action. Population reductions
may help reduce the dispersion of infected deer to non‐infected areas. Severe population
reductions within a reasonable area around the index case would likely be most effective in
scenarios where CWD appears to have been recently introduced and has not likely become
established in the environment (Brown et al. 2005). However, severe culling efforts have
been less popular in areas where CWD is well established, as hunters and the general public
eventually grow weary from the intensive culling practices that continue indefinitely.
Eradication Attempts – New York discovered CWD in two different captive herds during
routine CWD surveillance in 2005. They promptly initiated an intensive surveillance effort
within 10 miles of the infected premises, and confirmed CWD in two free‐ranging deer. It
appears that removal of those two deer at least temporarily prevented further spread of CWD,
as the disease has not been detected in any additional deer despite intensive sampling through
severe population reductions for the following five years (Brown et al. 2005). Intensive
culling also appeared to work in a similar situation in Minnesota, where CWD was confirmed
in a wild deer within three miles of an infected captive elk herd. Sharpshooters collected
almost 1,200 deer within the “Disease Zone” during the winter of 2011, and hunters provided
samples from 2,300 deer harvested during the following fall with no additional CWD
detected. It seems that the introduction of CWD into free‐ranging deer in Minnesota was
detected very early and establishment of the disease was prevented.
Control Attempts – However, in areas of Wyoming, Colorado, and Wisconsin where CWD
has been established for many years, eradication is an unrealistic management option. This is
likely the situation in the Hueco Mountains of west Texas, where limited sampling indicates
disease prevalence may average ~10% but may exceed 50% north of the Texas ‐ New
Mexico border.
In these situations, major population reductions would not prevent animals from contracting
CWD from the contaminated environment. In such situations, strategies to restrict or reduce
the movements of free‐ranging or captive cervids (and carcass parts) from CWD endemic
areas may effectively reduce the spread of CWD. Some states partner with hunters to help
monitor prevalence and distribution, as well as manage deer and elk populations to meet
CWD‐ management objectives. Several states, including Wyoming, also employ other
disease management strategies such as a ban on baiting, prohibiting unnatural (i.e., man‐
induced) movements of deer or carcasses, and general education efforts to encourage
responsible actions by hunters and other stakeholders.
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